To minimise the risk of having problems with warfarin:

• Let your healthcare professional know if your regular medicines change
• Check with your healthcare professional before starting any new medicines
• Tell the pharmacist that you take warfarin before buying over-the-counter (OTC) medicines
• Get advice from your healthcare professional before taking vitamins, minerals, herbal or natural therapies
• If you visit a different health professional make sure you tell them that you're taking warfarin

Aspirin also affects blood clotting and small doses of aspirin are used to stop heart attacks and strokes. If you are already taking aspirin when you start warfarin, check with your doctor whether you need to keep taking it. There are some conditions where people will need to take a combination of medicines that affect how their blood clots, for example some people may need to take aspirin and warfarin together while others may only need one or the other.

Aspirin in larger doses is used to treat pain and fevers. It is best to avoid larger doses of aspirin while taking warfarin. For pain or fever, paracetamol is safer than aspirin as long as it is used at the recommended dose. Check with your healthcare professional if you need treatment for long term pain.

It always best to seek advice from your healthcare professional before starting any new medicine while taking warfarin, especially alternative medicines. There are some alternative medicines that are safe to take with warfarin, but there are also many alternative medicines that interfere with the way warfarin works and are best avoided. Check with your healthcare professional about any that you might be interested in taking.